Can biologic drugs tackle antibiotic resistance?

Antibody-based products present a novel approach to the treatment and prevention of infections, as an alternative to conventional antibiotics. Several companies are developing such agents for a range of indications, but their cost, complex manufacturing methods and mode of administration are restrictive. A high unmet need and well defined target groups are key to commercial success in this market.

Increased interest in the development of antibody-based agents

Historically, serum-derived antibody therapy has been used to treat a wide range of infections, but safety concerns and the increased availability of anti-infective drugs have led to the slow decline of antibody agents over the past five decades. However, advances in technology have improved manufacturing costs and tolerability, leading to a renewed interest in the development of antibody-based agents for prophylaxis (prevention) and the treatment of infectious diseases. A key factor in gaining wider clinical acceptance is the fact that fully human antibody reagents avoid the toxicities associated with traditional human- or animal-derived serum therapy.

The emergence of new pathogens, combined with an increasing prevalence of drug-resistant microorganisms, has compromised the efficacy of existing therapeutic options. Moreover, old pathogens have re-emerged as the difficulties involved in preventing and treating infections in immuno-compromised patients have highlighted the need for adjunctive immunotherapy. Despite the approval of the first monoclonal antibodies more than 20 years ago, only one antibody product has been successfully approved for an infectious disease indication; Medimmune's Synagis, a humanized antibody for the prophylaxis of respiratory syncytial virus. The drug's annual sales are now approaching $1 billion, following its approval in 1998. Its follow-on product, motavizumab, was filed with the FDA in February 2008.

Now, however, several companies, including Genentech, have such products in development for a range of infections. However, the benefits of monoclonal antibodies are still largely offset by their cost, complex manufacturing methods and mode of administration, all of which will restrict their use to the treatment of certain infections. Consequently, a high unmet need, as well as precisely defined target groups, is invaluable if the favorable efficacy and cost-benefit profiles, which are required to convince the regulatory and reimbursement gatekeepers, are to be demonstrated. Antibody-based products that fulfill these criteria have a reasonable probability of commercial and scientific success.